Theoretically, it is a kind of reversible reactions : charged and discharged. But batteries do aging. It is because of the microstructure of the materials : The porosity is degrading, so reacting area or active area deduces over time, sintering etc..

Theoretically, it is a kind of reversible reactions : charged and discharged. But batteries do aging. It is because of the microstructure of the materials : The porosity is degrading, so reacting area or active area deduces over time, sintering etc..